15 research outputs found
Dissipative hydrodynamics and heavy ion collisions
Space-time evolution and subsequent particle production from minimally
viscous (=0.08) QGP fluid is studied using the 2nd order
Israel-Stewart's theory of dissipative relativistic fluid. Compared to ideal
fluid, energy density or temperature evolves slowly in viscous dynamics.
Particle yield at high is increased. Elliptic flow on the other hand
decreases in viscous dynamics. Minimally viscous QGP fluid found to be
consistent with a large number of experimental data.Comment: 8 pages, 13 figures. Revised version of the invited talk at the 20th
International conference on Ultra-Relativistic Nucleus Nucleus collisions
(Quark Matter 2008), Feb. 4-10, 2008, Jaipur, Indi
Hydrodynamics at RHIC -- how well does it work, where and how does it break down?
I review the successes and limitations of the ideal fluid dynamic model in
describing hadron emission spectra from Au+Au collisions at the Relativistic
Heavy Ion Collider (RHIC).Comment: 8 pages, 4 figures. Invited talk presented at Strange Quark Matter
2004 (Cape Town, Sep. 15-20, 2004). Proceedings to appear in Journal of
Physics
New Formulation of Causal Dissipative Hydrodynamics: Shock wave propagation
The first 3D calculation of shock wave propagation in a homogeneous QGP has
been performed within the new formulation of relativistic dissipative
hydrodynamics which preserves the causality. We found that the relaxation time
plays an important role and also affects the angle of Mach cone.Comment: 4 pages, 1 figure, Proceedings of Quark Matter 200
Second Order Dissipative Fluid Dynamics for Ultra-Relativistic Nuclear Collisions
The M\"uller-Israel-Stewart second order theory of relativistic imperfect
fluids based on Grad's moment method is used to study the expansion of hot
matter produced in ultra-relativistic heavy ion collisions. The temperature
evolution is investigated in the framework of the Bjorken boost-invariant
scaling limit. The results of these second-order theories are compared to those
of first-order theories due to Eckart and to Landau and Lifshitz and those of
zeroth order (perfect fluid) due to Euler.Comment: 5 pages, 4 figures, size of y-axis tick marks for Figs. 3 and 4 fixe
Hydrodynamics and Flow
In this lecture note, we present several topics on relativistic hydrodynamics
and its application to relativistic heavy ion collisions. In the first part we
give a brief introduction to relativistic hydrodynamics in the context of heavy
ion collisions. In the second part we present the formalism and some
fundamental aspects of relativistic ideal and viscous hydrodynamics. In the
third part, we start with some basic checks of the fundamental observables
followed by discussion of collective flow, in particular elliptic flow, which
is one of the most exciting phenomenon in heavy ion collisions at relativistic
energies. Next we discuss how to formulate the hydrodynamic model to describe
dynamics of heavy ion collisions. Finally, we conclude the third part of the
lecture note by showing some results from ideal hydrodynamic calculations and
by comparing them with the experimental data.Comment: 40 pages, 35 figures; lecture given at the QGP Winter School, Jaipur,
India, Feb.1-3, 2008; to appear in Springer Lecture Notes in Physic
Nonequilibrium models of relativistic heavy-ion collisions
To be published in J. Phys. G - Proceedings of SQM 2004 : We review the results from the various hydrodynamical and transport models on the collective flow observables from AGS to RHIC energies. A critical discussion of the present status of the CERN experiments on hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A.GeV: here the hydrodynamic model has predicted the collapse of the v2-flow ~ 10 A.GeV; at 40 A.GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as evidence for a first order phase transition at high baryon density r b. Moreover, the connection of the elliptic flow v2 to jet suppression is examined. It is proven experimentally that the collective flow is not faked by minijet fragmentation. Additionally, detailed transport studies show that the away-side jet suppression can only partially (< 50%) be due to hadronic rescattering. Furthermore, the change in sign of v1, v2 closer to beam rapidity is related to the occurence of a high density first order phase transition in the RHIC data at 62.5, 130 and 200 A.GeV
A consistent first-order model for relativistic heat flow
This paper revisits the problem of heat conduction in relativistic fluids,
associated with issues concerning both stability and causality. It has long
been known that the problem requires information involving second order
deviations from thermal equilibrium. Basically, any consistent first-order
theory needs to remain cognizant of its higher-order origins. We demonstrate
this by carrying out the required first-order reduction of a recent variational
model. We provide an analysis of the dynamics of the system, obtaining the
conditions that must be satisfied in order to avoid instabilities and acausal
signal propagation. The results demonstrate, beyond any reasonable doubt, that
the model has all the features one would expect of a real physical system. In
particular, we highlight the presence of a second sound for heat in the
appropriate limit. We also make contact with previous work on the problem by
showing how the various constraints on our system agree with previously
established results.Comment: RevTeX, 1 eps Figur
Space-time evolution and HBT analysis of relativistic heavy ion collisions in a chiral SU(3) x SU(3) model
The space-time dynamics and pion-HBT radii in central heavy ion-collisions at
CERN-SPS and BNL-RHIC are investigated within a hydrodynamic simulation. The
dependence of the dynamics and the HBT-parameters on the EoS is studied with
different parametrisations of a chiral SU(3) sigma-omega model. The
selfconsistent collective expansion includes the effects of effective hadron
masses, generated by the nonstrange and strange scalar condensates. Different
chiral EoS show different types of phase transitions and even a crossover. The
influence of the order of the phase transition and of the difference in the
latent heat on the space-time dynamics and pion-HBT radii is studied. A small
latent heat, i.e. a weak first-order chiral phase transition, or even a smooth
crossover leads to distinctly different HBT predictions than a strong first
order phase transition. A quantitative description of the data, both at SPS
energies as well as at RHIC energies, appears difficult to achieve within the
ideal hydrodynamical approach using the SU(3) chiral EoS. A strong first-order
quasi-adiabatic chiral phase transition seems to be disfavored by the pion-HBT
data from CERN-SPS and BNL-RHIC
Derivation of fluid dynamics from kinetic theory with the 14--moment approximation
We review the traditional derivation of the fluid-dynamical equations from
kinetic theory according to Israel and Stewart. We show that their procedure to
close the fluid-dynamical equations of motion is not unique. Their approach
contains two approximations, the first being the so-called 14-moment
approximation to truncate the single-particle distribution function. The second
consists in the choice of equations of motion for the dissipative currents.
Israel and Stewart used the second moment of the Boltzmann equation, but this
is not the only possible choice. In fact, there are infinitely many moments of
the Boltzmann equation which can serve as equations of motion for the
dissipative currents. All resulting equations of motion have the same form, but
the transport coefficients are different in each case.Comment: 15 pages, 3 figures, typos fixed and discussions added; EPJA: Topical
issue on "Relativistic Hydro- and Thermodynamics
Hydrodynamic afterburner for the CGC at RHIC
Firstly, we give a short review about the hydrodynamic model and its
application to the elliptic flow phenomena in relativistic heavy ion
collisions. Secondly, we show the first approach to construct a unified model
for the description of the dynamics in relativistic heavy ion collisions.Comment: 15 pages, 7 figures, invited talk presented at "Hot Quarks 2004",
July 18-24, 2004, Taos Valley, NM, US